My favourite and most commonly used word is definitely yabai (やばい）… I’ve heard many of my native friends use it as well. It can be used for many situations like “Ah! What?” … “That’s dangerous”… “oh no!” … “Oh my, she is so pretty!” …

Everyone always picks some word that stands out as their favorite, but my favorite is 最近（さいきん）(recently). When a Japanese guy asked me what my favorite word was, he was really surprised since it’s a completely normal word, but I really love how it sounds, and I also love writing out the kana.

A runner up would be 言語道断（ごんごどうだん）(ridiculousness). I love this one because it kinda describes itself.

god i really can’t pick one, there are so many i like from different word classes, onomatopoeia, wasei, yoji, compound verbs… but the ones that happened to strike my fancy today, at least, are the loanwords-become-godan-verbs: ダブる、ググる、トラブる、サボる.

Mine would be しんきろう. The way it sounds immediately reminds me of fog, and a garden in a rainy season. Its meaning is fatamorgana. I discover this word from Sakanaction and TK from Ling Tosite Sigure’s track.